Optic flow improves step width and length in older adults while performing dual task

Leeder, Taylor; Fallahtafti, Farahnaz; Schieber, Molly; Myers, Sara A.; Boron, Julie Blaskewicz; Yentes, Jennifer M.

doi:10.1007/s40520-018-1059-x

Cited by 7 publications

(5 citation statements)

References 35 publications

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“…Similar to previous reports [ 16 , 23 , 48 ], we found that the type of the secondary task modulated the magnitude of dual-task gait decline in older adults. Counting backward led to the greatest interference for older adults as evidenced by the high DTC for both cognitive task and gait speed (Fig.…”

Section: Discussionsupporting

confidence: 91%

“…Based on this model, each attentional resource may show different degrees of susceptibility to brain injury or aging and lead to task-dependent dual-task interference in different populations [ 15 , 18 ]. However, the task-dependency in dual-task walking has been limited examined in geriatric research [ 22 , 23 ]. Al-Yahya and colleagues performed a meta-analysis to compare the effect of different cognitive task domains on dual-task gait in healthy and neurological populations.…”

Section: Introductionmentioning

confidence: 99%

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Task matters: an investigation on the effect of different secondary tasks on dual-task gait in older adults

2021

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Background Dual-task gait performance declines as humans age, leading to increased fall risk among older adults. It is unclear whether different secondary cognitive tasks mediate age-related decline in dual-task gait. This study aimed to examine how type and difficulty level of the secondary cognitive tasks differentially affect dual-task gait in older adults. Methods Twenty young and twenty older adults participated in this single-session study. We employed four different types of secondary tasks and each consisted of two difficulty levels, yielding eight different dual-task conditions. The dual-task conditions included walking and 1) counting backward by 3 s or by 7 s; 2) remembering a 5-item or 7-item lists; 3) responding to a simple or choice reaction time tasks; 4) generating words from single or alternated categories. Gait speed and cognitive task performance under single- and dual-task conditions were used to compute dual-task cost (DTC, %) with a greater DTC indicating a worse performance. Results A significant three-way interaction was found for the gait speed DTC (p = .04). Increased difficulty in the reaction time task significantly increased gait speed DTC for older adults (p = .01) but not for young adults (p = .90). In contrast, increased difficulty level in the counting backward task significantly increased gait speed DTC for young adults (p = .03) but not for older adults (p = .85). Both groups responded similarly to the increased task difficulty in the other two tasks. Conclusions Older adults demonstrated a different response to dual-task challenges than young adults. Aging might have different impacts on various cognitive domains and result in distinctive dual-task gait interference patterns.

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Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Task matters: an investigation on the effect of different secondary tasks on dual-task gait in older adults

2021

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“…Although participants did not acclimate to the presence of optical flow per se, we randomized the order of walking trials such that any adjustments to optical flow would not affect average differences in our primary outcomes due to the onset of perturbations. Indeed, we would expect unperturbed optical flow to have little effect on gait biomechanics, as was shown with step width in older adults [55]. We did not administer a formalized questionnaire to assess the prevalence of motion sickness in our subject cohorts.…”

Section: Plos Onementioning

confidence: 94%

Can optical flow perturbations detect walking balance impairment in people with multiple sclerosis?

et al. 2020

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People with multiple sclerosis (PwMS) who exhibit minimal to no disability are still over twice as likely to fall as the general population and many of these falls occur during walking. There is a need for more effective ways to detect preclinical walking balance deficits in PwMS. Therefore, the purpose of this study was to investigate the effects of optical flow perturbations applied using virtual reality on walking balance in PwMS compared to age-matched controls. We hypothesized that susceptibility to perturbations-especially those in the mediolateral direction-would be larger in PwMS compared to controls. Fourteen PwMS and fourteen age-matched controls walked on a treadmill while viewing a virtual hallway with and without optical flow perturbations in the mediolateral or anterior-posterior directions. We quantified foot placement kinematics, gait variability, lateral margin of stability and, in a separate session, performance on the standing sensory organization test (SOT). We found only modest differences between groups during normal, unperturbed walking. These differences were larger and more pervasive in the presence of mediolateral perturbations, evidenced by higher variability in step width, sacrum position, and margin of stability at heel-strike in PwMS than controls. PwMS also performed worse than controls on the SOT, and there was a modest correlation between step width variability during perturbed gait and SOT visual score. In conclusion, mediolateral optical flow perturbations revealed differences in walking balance in PwMS that went undetected during normal, unperturbed walking. Targeting this difference may be a promising approach to more effectively detect preclinical walking balance deficits in PwMS.

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“…In macaques, several studies have shown precise neuronal selectivity to optic flow stimuli [ 4 , 5 , 6 , 7 , 8 , 9 ], to the interaction between optic flow and ocular position [ 10 , 11 , 12 , 13 ], and to the interaction between optic flow and other sensory signals [ 14 , 15 , 16 ]. In humans, several studies have shown that specific optic flow stimuli are important for guiding locomotion [ 17 , 18 , 19 , 20 ] and for the postural control [ 21 , 22 , 23 , 24 , 25 ]. The picture arising from those studies is that the analysis of the optic flow stimuli is a predominantly cortical process preparatory for specific motor actions.…”

Section: Introductionmentioning

confidence: 99%

Sensory Input Modulates Microsaccades during Heading Perception

Raffi

Trofè

Perazzolo

et al. 2021

IJERPH

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Microsaccades are small eye movements produced during attempted fixation. During locomotion, the eyes scan the environment; the gaze is not always directed to the focus of expansion of the optic flow field. We sought to investigate whether the microsaccadic activity was modulated by eye position during the view of radial optic flow stimuli, and if the presence or lack of a proprioceptive input signal may influence the microsaccade characteristics during self-motion perception. We recorded the oculomotor activity when subjects were either standing or sitting in front of a screen during the view of optic flow stimuli that simulated specific heading directions with different gaze positions. We recorded five trials of each stimulus. Results showed that microsaccade duration, peak velocity, and rate were significantly modulated by optic flow stimuli and trial sequence. We found that the microsaccade rate increased in each condition from trial 1 to trial 5. Microsaccade peak velocity and duration were significantly different across trials. The analysis of the microsaccade directions showed that the different combinations of optic flow and eye position evoked non-uniform directions of microsaccades in standing condition with mean vectors in the upper-left quadrant of the visual field, uncorrelated with optic flow directions and eye positions. In sitting conditions, all stimuli evoked uniform directions of microsaccades. Present results indicate that the proprioceptive signals when the subjects stand up creates a different input that could alter the eye-movement characteristics during heading perceptions.

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Optic flow improves step width and length in older adults while performing dual task

Cited by 7 publications

References 35 publications

Task matters: an investigation on the effect of different secondary tasks on dual-task gait in older adults

Task matters: an investigation on the effect of different secondary tasks on dual-task gait in older adults

Can optical flow perturbations detect walking balance impairment in people with multiple sclerosis?

Sensory Input Modulates Microsaccades during Heading Perception

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